Authorities wonder how, why LIGHT PLANE CRASH AT THE WHITE HOUSE

WASHINGTON -- President Clinton and his family returned to the White House last night while the Secret Service and other investigators tried to unravel the mystery of a 38-year-old Maryland man who apparently stole a small plane from a rural airfield, then flew it to the White House where he crashed and died.

The Clintons were staying across Pennsylvania Avenue, in Blair House, when Frank Corder, an Aberdeen native, crashed a 1971 Cessna 150 onto the White House lawn at 1:49 a.m. yesterday. The first family had moved for several days while the White House air conditioning system underwent repairs.

Secret Service officials said they did not believe the pilot had a political grievance against Mr. Clinton -- and were not sure he even meant to hurt himself, let alone the president.

But relatives and friends said the dead man had a history o alcohol and drug abuse and was despondent over the recent breakup of his marriage. The New York Times quoted friends as saying he'd been using crack cocaine recently and had once talked of stealing a plane and killing himself.

But his brother John suggested another motive, noting that Mr. Corder had been impressed by a young German pilot who landed a Cessna in Moscow's Red Square in 1987 and "made a big name for himself."

The fatal episode in the heart of the nation's power structure plunged the president's protectors into the same sort of perplexed embarrassment that consumed the Kremlin after German student Mathias Rust flew low enough to evade Soviet radar and land his plane at the Soviets' seat of power.

Authorities were at an apparent loss to explain how someone could steal a plane, fly through or around two of the East Coast's major air traffic control zones -- over Baltimore-Washington International and Washington National airports -- follow 17th Street at low level directly into the aircraft exclusion zone around the National Mall, make a J-turn at the Washington Monument and head directly at the White House back yard. All this without provoking any security reaction.

No shots were fired as the plane approached the White House at treetop height. According to Special Agent Carl Meyer, security guards radioed the alarm and had time only "enough to run for cover."

The plane skidded 50 feet across the South Lawn, sheered some branches from a magnolia tree planted when Andrew Jackson was president in the 1830s, and came to rest against the mansion, two stories below the private presidential apartment and within sight of the Oval Office.

The nation's security services will now move quickly to attempt to plug the security gap that allowed the plane to enter a strict security zone around the White House, officials said. Treasury Secretary Lloyd M. Bentsen, who oversees the Secret Service, ordered a review completed within 90 days.

New security concerns

The incident raised new concerns about the protection of the first family against the possibility of a terrorist air attack. The first thing the Secret Service checked the plane's wreckage for yesterday was explosive devices.

"The first thing we had to determine was, what was the situation?" said Agent Meyer. "I mean, was this just a plane that ran out of gas? Did somebody have a heart attack? We just didn't have a good sense of what was involved here. Or was it a diversion? Was something going to come?"

Fire and rescue services and a bomb disposal unit were called. The pilot was declared dead by the Washington medical examiner at 3:25 a.m., apparently from injuries sustained in the crash.

Sen. David Pryor, a Democrat from Arkansas and a close frien of Mr. Clinton's, noted that millions of dollars had been spent on ++ White House security, adding: "I just don't know why it did not function. Maybe it malfunctioned."

The embarrassing security breach started, officials said, whe the red-and-white Cessna 150 was stolen from the Harford County Airpark. The airport manager, Joseph V. Kessner, said the plane was still there when he left for home at about 7 p.m. Sunday.

Plane rented earlier

Earlier in the day, the plane had been rented and was returned with enough fuel for slightly more than 3 hours of flying left in its 13 gallon tank, Mr. Kessner said.

Mr. Corder, according to his brother, John, 41, had held a pilot' ++ license for about 10 years. "He certainly knew what he was doing around planes, and how to fly one. That's for sure," he said.

The precise flight path Mr. Corder followed was not disclosed, but aviation experts said a direct flight from the Harford County Airpark to downtown Washington would have taken him directly over the air traffic control tower at BWI Airport and on into the air control zone of Washington National Airport.